Grid structure



JuneZL 1949. B. c. GARDNER 2,473,793

GRID STRUCTURE Fild Oct. 26, 1945 'wnwra/f arm/mm a 66mm /6 Patented June 21, 1949 UNITEDSTATES PATENT OFFICE can) STRUCTURE Bernard 0. Gardner, Waltham, Mass., assignor to Raytheon Manufacturing Company, Newton, Mass., a corporation-of Delaware Application October 26, 1945, Serial No. 624,844

2 Claims. (01. 250-275) This invention relates to grid structures for electron-discharge devices, and while not limited thereto, it is especially suitable for use in electron-discharge devices of the type in which an electron beam is adapted to be velocity modulated.

During the operation of devices of the general character indicated, the grid structures thereof become quite hot. The resulting distortion of the shape of such grid structures alters the interelectrode spacing of the device, and this, in turn, causes undesirable frequency drift. Grid structures heretofore made rigid in an effort to avoid this difficulty include a multiplicity of parts which require careful and, therefore, costly assembling.

Hence, it is among the objects of the present invention to provide a grid structure, suitable for use as aforesaid, which is of integral and, therefore, simple construction, which is easy and economical to fabricate, and which is more eflicient in the performance of its intended function than the prior art structures.

These, and other objects of the present invention, which will become more apparent as the detailed description thereof progresses, are attained, briefly, in the following manner:

An annular member, for example, a tubular or cylindrical member, is closed at one end thereof, said closed end being provided with a plurality of radial slots dividing said closed end into a plurality of wedge-shaped fingers. These fingers are twisted at the bases thereof until they lie in planes parallel to the axis of the annular member. Alternat fingers are shortened so as to reduce the ratio of metal-to-space, when viewing the annular member endwise, and thus prevent too much interference with the electron beam intended to be acted upon. At the opposite end of the annular member, an outwardlydirected flange is provided by means of which the structure can be connected to an external circuit.

A structure such as that just described is rigid, and is made in one piece, thereby eliminating the disadvantages associated with the prior art.

In the accompanying specification there shall be described, and in the annexed drawings shown, an illustrative embodiment of the grid structures of the present invention. It is however, to be clearly understood that the present invention is not to be limited to the details herein shown and described for purposes of illustration only, inasmuch as changes therein may be made without the exercise of invention, and within the true 2 spirit and scope of the claims hereto appended.

In said drawings,

Fig. l is a longitudinal sectional view taken substantiallythrough the center of a velocitymodulated electron-discharge device of the type known as a reflex Klystron, said device incorporating grid structures made in accordance with the principles of the present invention;

Fig. 2 is an end view of an annular member utilized in making the grid structures of the present invention, said member being. shown at an intermediate stage in the manufacture thereof;

Fig. 3 is a, similar view of the same member after completion; and

Fig. 4 is a transverse sectional view taken on line 44 of Fig. 3.

Referring now more in detail to the aforesaid illustrative embodiment of the present invention, with particular reference to the drawing illustrating the same, the numeral It] generally designates a, velocity-modulated electron-discharge device, commonly known as a Klystron, more especially, a reflex Klystron. It is to be understood that the present invention is not limited to this type of device.

Said device l0 includes a base II supporting an evacuated glass envelope [2. The envelope I2 may be provided with a re-entrant press (not shown) supporting a highly electron-emissive cathode l3 adapted to be heated to a temperature suitable to bring about copious emission by a filament l4. Said cathode l3 may be surrounded by an accelerating electrode 15.

A pair of appropriately spaced grid structures l6 and I! is supported in advance of the cathode l3, for example, as by being sealed through the walls of the envelope l2, said grid structures, which will later be described in detail, being adapted to be connected, for example, to points of opposite potential on a cavity resonator I8, herein shown, in dotted lines, in the form of a toroid.

A repeller electrode I9 is supported beyond the grid structures l6 and I! from a lead-in conductor 20 entering the envelope 12 through the end thereof opposite the base II.

The grid structure [6 comprises a tubular member 2i, made of highly conductive material, such as copper, one end of which is initially closed. As best seen in Fig. 2 of the drawing, said closed end is provided with a plurality of radial slots 22 to divide the same into a plurality of substantially wedge-shaped fingers 23. The central portions of the fingers 23 are punched out to provide the structure with a central opening 24, and alternate fingers are further cut away to reduce the metal-to-space ratio in the central region of the structure and thereby prevent undue interference with the electron beam intended to be acted upon. As best seen in Figs. 3 and 4 of the drawing, the fingers 23 are twisted at the bases thereof, as at 25, until they lie in planes parallel to the axis of the tubular member 2|.

The opposite open end of the tubular member 2| is provided with an outwardly-directed flange 26 by means of which the structure may be sealed through the tube envelope I2 and connected, as previously indicated, to, for example, the cavity resonator IS.

The grid structure I! is substantially similar to the grid structure I6, except that the tubular body portion thereof may, if found desirable, :be of shorter length.

This completes the description of the aforesaid illustrative embodiment --of the grid structures of the present invention. It will -be noted that said grid structures are of integral construction, are rigid, are easy and inexpensive to make, and enable the maintenance of constant 'interelec- :trode spacing, which, particularly in electrondischarge devices of the type to which reference has herein been made, is necessary "to eliminate frequency drif t.

Other objects and advantages of the present invention will readily :occur to those skilled inthe art to which the same relates.

What is claimed is:

1. A grid structure for an electron-discharge device comprising: a tubular member having integrally formed, at one end thereof, a plurality of inwardly-directed, radially-disposed fingers, and at the other end thereof, an annular flange for connecting the same to an external circuit.

2. A rid structure for an electron-discharge device comprising: a tubular member having integrally formed, at one end thereof, a plurality ef inwardly-directed, radially-disposed, wedgexshaped fingers, and at the other end thereof, an

annular flange for connecting the same to an external circuit; Said fingers lying in planes parallel to the axis of said tubular member.

BERNARD C. GARDNER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

